Spark-plug.



G. A. ARNOLD.

SPARK PLUG.

APPLICATION FILED JUNE 28.1915.

1 EMS/6"? Patented Oct. 31,1916.

, snares nananar GEORGE A. ARNOLD, ll/IIDDLETOWN, CONNECTICUT, ASSIGNOB- T ARNOLD ELECTRIC COMPANY, A CORPORATION OF MASSACHUSETTS.

SPARK-PLUG.

wearer.

Specification of Letters Patent.

Patented il et. 833i, T93 165.

Application filed. June 28', 1915. Serial No. 36,703.

To all whom it may concern Be it known that I, GEORGE A. ARNOLD, citizen of the'United States, residing at Middletown, in the county of Middlesex and State of Connecticut, have. invented certain new and useful Improvements in Spark- Plugs, of which the following is a specification, reference being had to the accompanying drawings, forming part thereof.

This invention has reference to improvements in spark plugs, so called, by means of which disruptivedischarges of electricity or electric sparks may be produced.

Une object of the invention is to so construct a spark plug that the electric discharges between certain members thereof may be intensified and at the same time the.

discharges may be multiplied.

Another object of the invention is to improve the general construction of spark plugs particularly as regards the insulator whereby the exterior of said insulator may have a larger diameter than the inner por; tion.

Other objects of the invention will appear from the following description.

The invention consists in spark plugs having the novel sparking terminals.

The invention also consists in the construction of the spark, plug.

The invention also consists in such other 'novel features of construction and combination of parts as shall hereinafter be more fully described and pointed out in the claims. A

Figure 1, represents a side elevation of the improved spark plug. Fig. 2, represents a similar view, parts of the same being shown in section as. on line 22, Fig. 3. Fig. 3, represents an enlarged end view of the same. Fig. 4, represents an enlarged sectional view takenv on line at-%, Fig. 2. Fig. 5, represents an enlarged sectional view taken on line 22 Fig. 3 to show details of construction of some of the parts. Similar characters of reference designate corresponding parts throughout.

In carrying this invention into practice I construct the bushing 5 having the exterior screw thread 6 at one end, and at its outer end a socket having the seat 7 embracing the bore of the bushing, and the seat 8 which has the screw threaded extension collar 9 to receive the threaded portion of the split nut 10the members of which have in their outer shown in Fig. 1.

ends depressions which have the lips or walls 11, 11. Mounted in the material. of the inner end of said bushing 5 is the elec trode terminal 12.

The electric insulator is axially perforated 1 said head 13 and the annular shoulder 15 received by the bore of split or two-part nut 10; said shoulder 15 is adapted to be received by the socket at the outer end of bushing 5 whereby said shoulder 15 may seat against the asbestos washer 16 sustained by the seat 7. From the shoulder 15 extends the stem 17 of the insulator which is of a diameter less than-the diameter of the bore of bushing 5 and is furnished at its end with the socket 18.

' Extending through the axial perforation of the insulator is the: electrode 19 having at one end the binding screw 20 and binding member or cap 21and-at the other end the enlarged cup or receptacle 22 located within but spaced from the wall of the insulator socket 18 andhaving the inwardlybent terminals 23,23. In said cup 2. is located the insulator 24 secured in place by the bending of the edge of said cup 22 into the annular groove of this insulator 2st as is The insulator 24 has an axial perforation terminating at its inner end in the chamber or enlarged bore 25 and in said axial perforation is located the stem 26 having atits inner end the head 27 and at its outer end the terminal 28 which latter is of course thus electrically insulated from the terminals 23, 23 of electrode 19. The space between these terminals '23 and the sides of terminal 28'is considerably less than the space between said terminals 25}, 23 and the terminal 12.

If now the electrode 19 be connected with one arm of a suitable electric circuit and bushing 5 be connected with the other arm of said circuit, and a current of electricity .is supplied thereto the course of said curlot by the first spark seeking to jump between the terminals 23, 23 and 28.

By the use of the complemental nut members 10, 10, I am able to produce a spark plug in which the main insulator member is of large size and of great stability at the portion most exposed to shocks. 7

While I have herein shown a particular construction of my improved spark plug I do not intend thereby to limit my invention except as herein claimed.

Having thus described my invention 1 claim as new and desire to secure by Letters Patent- 1. A spark plug comprising a bushing having at one end a threaded socket larger than its bore, an insulator having a shoulder to fit saidsocket, an outer end member larger than said shoulder and an intervening neck, and a two-part nut adapted to embrace said neck and to be received by said socket, said two-part nut having a lip to receive and embrace said outermember of said in:

sulator.

2. A spark plug comprising a bushing electrode having a terminal, an electric insulator mounted in said bushing and having an axial perforation terminating in an enlarged bore, an electrode extending through GEORGE A. ARNOLD. 

